Smart card with extended surface module

ABSTRACT

A smart card includes a card bearing a module that is made up of a support supporting at least an electronic chip. The support is fixed on one surface of the card. This surface extends up to at least one of the edges of the card.

The present invention concerns a smart card and more precisely a smart card comprising a card bearing a module consisting of a support itself supporting at least one electronic chip, said support being fixed on a surface of the card.

A known smart card consists of a card made of plastic material of standardised format, two formats of which are the “bank card” type defined by ISO 7810 and the SIM “mini-card” type for mobile telephony. It bears an electronic module consisting of a support formed from a sheet of dielectric material possibly provided with printed circuits and supporting an electronic chip, for example an electronic memory. As a general rule, this chip is glued on one face of the support and protected by a coat of epoxy resin forming an extra thickness on the support. Hereinafter this face will be referred to as the rear face.

For fixing the module on the card, the latter comprises a first cavity of a first depth and a second cavity of a second depth implemented in the bottom of the first cavity and intended to receive chip and resin. The support is glued in the first cavity around the second cavity. The first cavity has a total surface equal to the surface of the module which is therefore installed by flush fitting therein. The thickness of such a card is standardised and approximately 800 microns, the first depth is approximately 200 microns and the second depth is approximately 400 microns.

What is sought at present is to store a large amount of data on such smart cards and consequently to install larger modules or to install several modules on a single card. This is in order to produce high-capacity memory cards capable of storing directories, music, films, etc.

The arrangement used at present has several problems.

The gluing surface for the module support can prove to be insufficient and lead to poor fixing of said module, in particular in the case of a large-sized chip. This is because this gluing surface is limited to the bottom of the first cavity apart from the second cavity receiving the chip and its protective resin. Consequently, the greater the total surface of the chip or chips, the more insufficient this gluing surface proves to be since the ratio of module surface to gluing surface decreases.

This arrangement also poses manufacturing problems. In view of the depth of the first cavity, approximately 200 microns, this cavity must be implemented at a distance from the edges of the card imposed by the requirements of the moulding process. This distance must also be approximately 200 microns minimum. In fact it is difficult and even impossible to reduce this distance, since it is impossible to inject the plastic material onto a very thin wall. This is a manufacturing requirement running counter to the need to increase the format of the modules, the format of the card being standardised.

The invention solves these problems and proposes a smart card comprising a card bearing a module consisting of a support itself supporting at least one electronic chip, said support being fixed on a surface of the card, characterised in that the surface extends up to at least one of the edges of the card.

In the case of a module comprising a chip of current standard size (that is approximately 10 mm×8 mm including the drop of protective resin), the solution of the invention makes it possible to-increase the gluing surface for the module on the card and therefore increase the reliability of said card. This increase in the gluing surface is obtained by increasing the surface of the support supporting the chip.

And above all, the invention allows reliable fixing of large-sized modules provided with one or more large-sized chips. This is because it is possible to increase the size of the second cavity without reducing the gluing surface for the module on the card.

The invention simplifies the method of manufacturing the card simplifying the step of moulding at the edge of the card in question, by elimination of the thin wall present along the edge of the card.

According to the preferred embodiment, said support extends over the entire surface of the card.

Advantageously, the card comprises a cavity for receiving said support extending up to at least one edge of the card and implemented by moulding or machining.

In addition, the card can comprise at least one cavity for receiving the chip.

Preferably, the smart card is a mini-card.

The invention is described hereinafter in further detail with the help of figures depicting only one preferred embodiment of the invention.

FIG. 1 is a front view of a detachable SIM (Subscriber Identification Module, for portable telephony) mini-card still attached to a presentation support of “bank card” format according to the prior art.

FIG. 2 is a sectional view along II-II of FIG. 1.

FIG. 3 is an analogous sectional view according to the invention.

The following description relates to a SIM mini-card for portable telephony, but the invention applies to any smart card, irrespective of its format and irrespective of its application.

A smart card 1 consists of a card made of plastic material of standardised format 2. It bears an electronic module consisting of a support 3 formed from a sheet of plastic material possibly provided with printed circuits and supporting an electronic chip 4, for example an electronic memory. As a general rule, this chip 4 is glued on a face of the support 3 and protected by a coat of epoxy resin forming an extra thickness on the support.

The figures depict a mini-card 1 attached to a support card of “bank card” format 5 having only a presentation function. In order to use the mini-card 1, it is detached by virtue of cuttable tongues surrounding it.

FIGS. 1 and 2 depict a smart card 1 according to the prior art.

For fixing the module 3, 4 on the card 2, the latter comprises a first cavity 6 of a first depth and a second cavity 7 of a second depth implemented in the bottom of the first cavity 6 and intended to receive chip and resin 4. The support 3 is glued in the first cavity 6 around the second cavity 7. The first cavity 6 has a total surface equal to the surface of the module 3, 4 which is therefore installed by flush fitting therein.

The gluing surface for the module is therefore equal to the surface of the first cavity S6 minus the surface of the second cavity S7.

FIG. 3 is a sectional view analogous to the section of FIG. 2 according to the invention.

Here, the gluing surface for the module 3, 4 is equal to the surface S of the card 2 minus the surface of the cavity S7 intended to receive the chip and the resin 4.

According to the invention, the gluing surface extends up to at least one of the edges of the card 2 and preferably, as depicted, it extends up to all the edges of the card 2. In other words, the support 3 of the glued module extends over the entire surface of the card 2. And in this case, only the cavity 7 is implemented on the card 2 of thickness less than that according to the prior art. This cavity 7 can be implemented by moulding or machining.

The invention therefore makes it possible, with a standardised card size, to increase the gluing surface for the module 3, 4 on the card 2 and therefore increase the reliability of said card.

It also makes it possible essentially to fix, on this card, larger-sized modules provided with larger-sized chips or a greater number of chips. It is self-evident that several cavities 7 can be implemented on the card 2 for receiving several chips. 

1. A smart card comprising a card bearing a module consisting of a support with at least one electronic chip attached thereto, said support being fixed on a surface of said card, wherein said surface extends up to at least one of the edges of said card.
 2. A smart card according to claim 1, wherein said support extends over the entire surface of said card.
 3. A smart card according to claim 1, wherein said card comprises a cavity for receiving said support extending up to at least one edge of said card and implemented by moulding.
 4. A smart card according to claim 1, wherein said card comprises a cavity for receiving said support extending up to at least one edge of said card and implemented by machining.
 5. A smart card according to claim 1, wherein said card comprises at least one cavity for receiving the chip.
 6. A smart card according to claim 1, wherein said smart card is a mini-card.
 7. A smart card comprising: a substrate having a defined size and shape and a cavity in one surface thereof; and a module consisting of a support sheet having the same size and shape as said substrate and an electronic chip attached to a mounting surface thereof, said mounting surface of said support sheet facing said one surface of said substrate so that said electronic chip is disposed within said cavity. 